python - Convert generator object to list for debugging

Question

When I'm debugging in Python using IPython, I sometimes hit a break-point and I want to examine a variable that is currently a generator. The simplest way I can think of doing this is converting it to a list, but I'm not clear on what's an easy way of doing this in one line in ipdb, since I'm so new to Python.

Answer 1

只需调用list生成器即可。

lst = list(gen)
lst

请注意，这会影响不会返回任何其他项目的生成器。

您也不能直接list在 IPython 中调用，因为它与列出代码行的命令冲突。

对此文件进行了测试：

def gen():
    yield 1
    yield 2
    yield 3
    yield 4
    yield 5
import ipdb
ipdb.set_trace()

g1 = gen()

text = "aha" + "bebe"

mylst = range(10, 20)

运行时：

$ python code.py 
> /home/javl/sandbox/so/debug/code.py(10)<module>()
      9 
---> 10 g1 = gen()
     11 

ipdb> n
> /home/javl/sandbox/so/debug/code.py(12)<module>()
     11 
---> 12 text = "aha" + "bebe"
     13 

ipdb> lst = list(g1)
ipdb> lst
[1, 2, 3, 4, 5]
ipdb> q
Exiting Debugger.

转义函数/变量/调试器名称冲突的通用方法

有调试器命令p，pp它会print和prettyprint它们后面的任何表达式。

所以你可以按如下方式使用它：

$ python code.py 
> /home/javl/sandbox/so/debug/code.py(10)<module>()
      9 
---> 10 g1 = gen()
     11 

ipdb> n
> /home/javl/sandbox/so/debug/code.py(12)<module>()
     11 
---> 12 text = "aha" + "bebe"
     13 

ipdb> p list(g1)
[1, 2, 3, 4, 5]
ipdb> c

还有一个exec命令，通过在你的表达式前面加上前缀来调用!，它强制调试器将你的表达式作为 Python 表达式。

ipdb> !list(g1)
[]

有关更多详细信息，请参阅help p，help pp以及help exec在调试器中的时间。

ipdb> help exec
(!) statement
Execute the (one-line) statement in the context of
the current stack frame.
The exclamation point can be omitted unless the first word
of the statement resembles a debugger command.
To assign to a global variable you must always prefix the
command with a 'global' command, e.g.:
(Pdb) global list_options; list_options = ['-l']